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Interior Paint
Latex ,Vinyl, Acrylic (waterbased)
Advantages: Usually cheaper, Fade Resistant, easier clean up environmentally friendlier, faster drying, requires no special thinners or solvents, requires stirring less often. Less dust pick-up. Preferred for walls, ceilings and primed woodwork.
OilBased,Enamels,Alkyd
Advantages: Better flow properties, allowing for a smoother finish. Harder more scrub able, stronger bond to many surfaces, slower set up time allowing more time to work a particular area.
Preferred for Wood trim, cabinets, metal surfaces (heat registers, metal doors ect.)
New Work
New Wood
Primer: new woodwork should first be primed with a suitable primer. Generally an oil\alkyd interior primer is the most common for several reasons. 1 it does NOT raise the grain of the wood in the same manner that latex would. 2 better results sanding for a good prep job. 3 it can easily be painted with oil or latex. 4 Some of the resinous vehicle can penetrate into some wood surfaces for a very strong bond.
Today however there are more water born products available to be used as an interior wood primer such as Red Enz UNDERKOTE. Knots will have to be pigmented Stain Blocker used to prevent bleeding.
Finish paint The latex & water based paints are becoming more popular for woodwork as new products become available. Many still prefer the flowed out surface & harder finish of the oil-based .If a high gloss is desired you will generally get better results with an oil paint, but most people agree that the advantages of latex make for an over all easier job.
New Sheetrock , New Plaster
Latex is the most popular choice for sheetrock and plastered surfaces today.
Primer Latex finish paint can often be used as its own primer however; it is recommended that you use a quality latex drywall primer or primer-sealer for best results. This primer will penetrate somewhat into the surface for a good bond and creates a barrier for the finish coat to bond to for a more uniform appearance. It is probably best to stay away from the cheaper wallboard primers, as they have no surface properties and would not leave a suitable base for some finishes. There are oil-based primers that may be used for this purpose, but for the most part stick with the latex. New Plaster usually requires a cure time prior to painting check with the plaster manufacturers specifications.
Finish Paint: Latex Paint will bond to latex or oil primer. Oil finish paint will bond to the latex or oil primer, but may not always work out so well over the latex due to the higher flexibility of the latex.
New Hardboard
Primer :Unprimed hardboard may produce some bleed through with latex primer, its usually recommended to use an oil base /alkyd primer for these products. However with the wide array of materials available ,it it wise to check with the manufacturer as with some of the newer cement composition siding products it is recommended to primed with latex
Finish Paint :Latex Paint will bond to latex or oil primer. Oil finish paint will bond to the latex or oil primer, but may not always work out so well over the latex due to the higher flexibility of the latex
Previously Painted Surface
It's not usually necessary to prime previously painted surfaces. Any bare wood or patched areas should be spot primed with appropriate primer as described a new surface .
Stains, knots and graffiti need to be sealed see section below.
Ceilings :Applying a quality latex primer sealer to ceilings prior to paining with the finish will often give better results , it eliminates the splotchy look. Some of these latex sealers dry glossy, but the flat will be easier to paint over with the ceiling paint.
Painting over flat latex finish paint with a glossier finish paint will probably leave splotchy results. To prevent this first apply a quality wallboard primer or latex primer sealer .However it will often work ok just to use two coats of the finish paint as the first coat acts as the sealer.
Finish :You should always consider the type of paint presently on the surfaces. If the surface has been painted with latex last time, then it may be best to stick with latex for the work. This is because the latex will expand and contract farther than the oil-based, in time oil over latex could lead to problems. If a surface has been previously painted with oil, latex may not bond to that surface as well as oil-based paint, especially if the surface is glossy .The gloss would at least have to be dulled down prior to painting or use an adhesion promoting primer such as Red Enz Stain Blocka.
Stains Knots Graffiti Discolored Ceilings
There are latex ,alkyd and alcohol based primer sealers.(see Red Enz Stain Blocka range) Water stains on ceilings and walls, ink, crayon, and knots will need to be sealed prior to painting. Generally you only need to spot prime these areas.
The alcohol based is usually most effective. The alkyd next and latex the least effective. However they are easiest to use in the reveres order .
Knots will need the alcohol based sealer.
Water stains will usually cover with the alkyd or alcohol sealer
A discolored ceiling may not paint well with even two or more coats of ceiling paint. Using a good quality latex primer sealer prior to the finish ceiling paint give the best results.
Smoked up areas usually fair better using the oil or alcohol primer sealer
Wallpaper
Vinyl and older type non-vinyl wallpaper can be painted, often without a primer. However in many cases using the appropriate can reduce the chances of problems. A quality primer sealer is a good choice to insure a good bond to vinyl wallpaper and seal any color from bleeding. It is possible that the non-vinyl wallpapers can lift when painted with a latex paint or a latex primer sealer, therefore an oil based primer sealer would be recommended on older type wallpapers. Once the paper is primed it can be painted with oil or latex finish paint
Metal
Most new metal installations come pre-finished, or primed. Any bare un-oxidized ferrous metals should be primed with the proper type metal primer. Ferrous metals (steel, iron) can usually be primed with a standard gray or white metal primer. Oil Based
Galvanized metal should be primed with a product designed for that purpose. Galvanized Metal Primer. Usually White.
Aluminum can be primed with the galvanized metal primer, or the standard gray primer. Latex also bonds to aluminum and can be used for a primer under latex finish paint.
On slightly rusted surfaces use gray metal primer. Heavily rusted surfaces use a red (Iron Oxide) metal primer.
In general; (but not a rule of thumb) the more rusted the surface, the darker the metal primer used should be. Other commercial grade primers are also available for certain exterior use.
Finish paint : Once properly primed, most metal interior metal surfaces can be painted with almost any quality paint. However metal door and heat registers usually fair better with an oil base/alkyd. Gloss Metal Enamels provide the most durability, but can sometimes be more difficult to work with, and the high gloss may be over bearing. Semi gloss or eggshell gloss trim paint is a good choice for steel doors.Exterior Paint
Advantages Of Oil VS. Latex
Latex(Waterbased) finishes: Resist fading, do not chalk, easy clean up, low voc, flexible, breathable (allows moisture to pass through), fast dry, requires no chemical solvents.
Oil finish(Alkyds): flows out during application, protects metal, washes well, resist smearing and marking, penetrates into chalky surfaces, After drying it will not become stuck to rubber weather stripping from contact, Strong initial bond to most surfaces.
Exterior Primer
New Wood: Any new unprimed wood should first be coated with a suitable primer before the finish paint is applied. Oil\Alkyd was once considered a better choice than latex for wood primer. One reason that the oil may seem to be the better choice is that many painters feel that it's resins will penetrate into the wood surface better than the fast drying latex. That is probably true to a certain extent, but where there is usually some moisture content in the exterior wood, the oil may not be able penetrate as much as it anticipated. Where latex paint will mix with water, some moisture content in the wood will not resist the latex primer. Another property of latex is that allows moisture to penetrate (Breaths) much more so than oil .The breath-ability of latex may help prevent paint from pealing when the moisture is drawn out through the siding by the difference in interior and exterior air conditions. Another benefit of latex is its flexibility, as the siding will expand and contract with temperature and humidity changes.
An advantage of using oil based primer for wood siding is it also makes a somewhat good metal primer that will seal nail heads protecting them from rust more so than the latex. Also the oil-based /Alkyd does not raise wood grain.
We would not recommend using a latex primer to be coated with an oil finish in most exterior cases due to the difference in flexibility, but an oil/alkyd primer under latex finish paint is a good method. However sometimes it is necessary to use an alkyd based stain sealer over a latex ceiling or wall paint
Whatever type of primer you chose, check the manufacturers label to be sure it is suitable for the materials you will be using it on, there may be conditions such as tannin bleed associated with certain kinds of wood. We have been quite pleased with some of our more recent experiments with the latex wood primer. Although latex primer has increased in popularity in recent years, many are still more confident in the oil/alkyd primer.
Previously painted wood(Exterior)
For the most part previously painted wood will not need to be primed, however spot priming all bare wood and rusted nail heads is important. If you will be using oil finish paint, then you should use oil based primer. If you will be using latex finish paint then you can use latex or oil primer. If there are a lot of rusted nail heads showing through, then you may choose to use the oil primer as it will usually seal metal better than latex.
Finish Paint
Wood Trim ,Wood Siding: Latex house paints have been out selling oil based house paints for years. For the most part the latex is the more practical choice, however there are cases where using oil will be preferred. Houses previously painted with oil based house paint may have developed a chalky surface. If this chalky surface were not washed prior to painting, latex paint would not develop as good a bond to the surface as the oil based paint. That's because the oil-based paint can penetrate through the chalk better than the latex can.
Chalking paint was a way of having a self cleaning building. The top surface of the paint gradually turns to a fine powder, which gets washed away with the rain leaving a cleaner outer appearance. But the chalky effect is not as desirable today as it use to be and most paint available is anti chalking, even so most exterior oil based paints will eventually chalk to a certain degree.
Oil /Alkyd is often the better choice for exterior doors. This is because often the latex paint, even completely dry will form a bond to certain rubber-like materials in which the doors weather stripping is made of. This will lead to pealing paint wherever the weather strip contacts the door.
Window sash is often easier to paint with oil, than with latex. If widows are being re-glazed with oil based glazing compound (Window Putty), they will need to be painted or at least primed with oil paint.
Vinyl Siding: Latex is generally preferred for vinyl siding. With a good quality latex paint, no primer will be necessary, but a latex bonding primer is a good idea on glossy siding .
Vinyl has a higher rate of thermal expansion than most building materials, in other words it will expand and contract further with temperature change. For that reason it is advised that you do not paint vinyl siding with a color that is darker than its original color, as dark colors draw solar heat. Individual siding manufacturers often have there own painting recommendations. Some manufacturers recommend not to paint it .
Aluminum Siding After washing, latex finish paint gives nice long lasting results no primer is usually required .Bare spots can be spot primed prior to painting with the finish paint
Window sash is often easier to paint with oil/alkyd, than with latex. If widows are being re-glazed with oil based glazing compound (Window Putty), they will need to be painted or at least primed with oil paint.
New Hardboard
Primer :Unprimed hardboard may produce some bleed through with latex primer, its usually recommended to use an oil base /alkyd primer for these products. However with the wide array of materials available, it it wise to check with the manufacturer, as with some of the newer cementasious siding products it is recommended that they are primed with latex.
Finish Paint :Latex Paint will bond to latex or oil primer. Oil finish paint will bond to the latex or oil primer, but may not always work out so well over the latex due to the higher flexibility of the latex
Metal Most new metal installations come pre-finished, or primed .Any bare un-oxidised should be primed with the proper type metal primer. Ferrous metals (steel, iron) can usually be primed with a standard gray or white metal primer .Oil Based
Galvanised metal should be primed with a product designed for that purpose. Galvanized Metal Primer. Usually White.
Aluminum can be primed with the galvanized metal primer, or the standard gray primer. Latex also bonds to aluminum and can be used for a primer under latex finish paint.
On slightly rusted surfaces use gray metal primer. Heavily rusted surfaces use a red (Iron Oxide) metal primer.
In general; (but not a rule of thumb) the more rusted the surface, the darker the recommended primer will be. Other commercial grade primers are also available for certain exterior use.Finish paint Once properly primed, most metal interior metal surfaces can be painted with almost any quality paint. However metal door and heat registers usually fair better with an oil base/alkyd. Gloss Metal Enamels provide the most durability, but can sometimes be more difficult to work with, and the high gloss may be over bearing. Semi gloss or eggshell gloss trim paint is a good choice for steel doors.
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